Boundary conditions on the early Sun from ancient cosmogenic neon in meteorites

Isotopic analysis of neon from individual grains of the meteorites Murchison (CM) and Kapoeta (howardite) shows large enrichments of cosmogenic neon in grains with solar flare tracks. The quantity of this component is incompatible with galactic cosmic ray or solar cosmic ray irradiation under present conditions and is attributed to irradiation by energetic flares from an early active Sun. Handpicked grains from each meteorite were grouped according to the presence or absence of solar flare heavy ion tracks, and these four samples were analyzed with an ion counting noble gas mass spectrometer

Evidence in meteorites for an active early Sun

The amounts of neon-21 found in meteorite particles indicate that the Sun experienced a period of intense solar flare activity approximately 4.5 billion years ago

Precompaction irradiation effects: Particles from an early active sun?

Two recent studies have shown that solar flare irradiated grains from Murchison and Kapoeta have excess spallogenic Ne-21 compared to unirradiated grains, indicating large precompaction particle irradiation effects. The quantity of cosmogenic neon in these grains presents serious difficulties for either galactic cosmic ray or normal solar flare sources. In the first study it was suggested that the effect might be the result of exposure to an early active sun. The more recent experiment both confirms the earlier results and provides constraints on the characteristic energy spectrum on the irradiation. The first results were obtained from Murchison olivines and Kapoeta pyroxenes by mass spectrometric analysis of sets of grains selected on the basis of the presence or absence of solar flare particle tracks. In the second work plagioclase feldspar grains from Kapoeta were studied

A Comparison of Early Childhood Health Indicators

The abstract for this presentation can be downloaded by clicking on the blue download button

Early Childhood Educators\u27 Self-Reported Food Insecurity Impact on Observed Classroom Food Environment

Peyton M. Percle is a research associate at the ENRICH Center, in the College of Applied and Natural Sciences at Louisiana Tech University. Emily A. Byley is a graduate student in the College of Education at Louisiana Tech University. Julie M. Rutledge is an Associate Professor in the School of Human Ecology, and the Director of ENRICH Center in the College of Applied and Natural Sciences, at Louisiana Tech University. Taren M. Swindle is an Assistant Professor at the University of Arkansas for Medical Sciences. The abstract for their presentation Early Childhood Educators\u27 Self-Reported Food Insecurity Impact on Observed Classroom Food Environment can be downloaded by clicking on the blue download button

The phosphoinositide 3-kinase-dependent activation of Btk is required for optimal eicosanoid production and generation of reactive oxygen species in antigen-stimulated mast cells

Activated mast cells are a major source of the eicosanoids PGD(2) and leukotriene C(4) (LTC(4)), which contribute to allergic responses. These eicosanoids are produced following the ERK1/2-dependent activation of cytosolic phospholipase A(2), thus liberating arachidonic acid, which is subsequently metabolized by the actions of 5-lipoxygenase and cyclooxygenase to form LTC(4) and PGD(2), respectively. These pathways also generate reactive oxygen species (ROS), which have been proposed to contribute to FcepsilonRI-mediated signaling in mast cells. In this study, we demonstrate that, in addition to ERK1/2-dependent pathways, ERK1/2-independent pathways also regulate FcepsilonRI-mediated eicosanoid and ROS production in mast cells. A role for the Tec kinase Btk in the ERK1/2-independent regulatory pathway was revealed by the significantly attenuated FcepsilonRI-dependent PGD(2), LTC(4), and ROS production in bone marrow-derived mast cells of Btk(-/-) mice. The FcepsilonRI-dependent activation of Btk and eicosanoid and ROS generation in bone marrow-derived mast cells and human mast cells were similarly blocked by the PI3K inhibitors, Wortmannin and LY294002, indicating that Btk-regulated eicosanoid and ROS production occurs downstream of PI3K. In contrast to ERK1/2, the PI3K/Btk pathway does not regulate cytosolic phospholipase A(2) phosphorylation but rather appears to regulate the generation of ROS, LTC(4), and PGD(2) by contributing to the necessary Ca(2+) signal for the production of these molecules. These data demonstrate that strategies to decrease mast cell production of ROS and eicosanoids would have to target both ERK1/2- and PI3K/Btk-dependent pathways

Uranium-lead Isotope Evidence in the Shelyabinsk LL5 Chondrite Meteorite for Ancient and Recent Thermal Events

The impact histories on chondrite parent bodies can be deduced from thermochronologic analyses of materials and isotope systems with distinct apparent closure temperatures. It is especially critical to better understand the geological histories and physical properties of potenally hazardous near-Earth asteroids. Chelyabinsk is an LL5 chondrite meteorite that was dispersed over a wide area tens of kilometers south of the town of Chelyabinsk, Russia by an explosion at an altitude of 27 km at 3:22 UT on 15 Feb 2013 [1,2]. The explosion resulted in significant damage to surrounding areas and over 1500 injuries along with meteorite fragments being spread over a wide area [1]

Adenovirus-mediated transfer of a gene encoding acyloxyacyl hydrolase (AOAH) into mice increases tissue and plasma AOAH activity

Although the host response to gram-negative bacterial infection follows largely from the interactions of bacterial lipopolysaccharides (LPS or endotoxin) with host cells, little information is available concerning the mechanisms by which the host eliminates or detoxifies LPS. Acyloxyacyl hydrolase (AOAH) is an enzyme, found in phagocytic cells, that catalyzes the enzymatic deacylation of the lipid A moiety of LPS. Enzymatically deacylated LPS is much less potent than LPS at inducing responses in human cells, and it can antagonize the ability of LPS to activate human macrophages, neutrophils, and endothelial cells. Despite these observations, the physiologic role of LPS deacylation remains undefined. To investigate the ability of AOAH to carry out LPS deacylation in vivo, we produced a recombinant adenovirus carrying a gene encoding AOAH (Ad.CMV-AOAH) and employed this vector to elicit transient overexpression of AOAH in mice. Mice infected with Ad.CMV-AOAH expressed high levels of the enzyme in plasma, liver, spleen, and kidney. Although adenovirus-induced hepatitis reduced hepatic uptake of intravenously injected [H-3]LPS, animals expressing the transgene deacylated a larger fraction of the [3H]LPS taken up by their livers than did mice infected with a control adenovirus. These studies indicate that AOAH can catalyze the deacylation of LPS in vivo, and they provide evidence that the rates of hepatic LPS uptake and deacylation are not closely linked

Mineral Surface and Fluid Chemistry in Nakhlite Analog Water-Rock Reactions

We report on experiments with Mars analog materials under diagenetic conditions and find characteristic chemical surface changes in correspondence with the fluid conditions